Crystal Structure of the Human LRH-1 DBD-DNA Complex Reveals Ftz-F1 Domain Positioning is Required for Receptor Activity.Solomon, I.H., Hager, J.M., Safi, R., McDonnell, D.P., Redinbo, M.R., Ortlund, E.A.
(2005) J Mol Biol 354: 1091-1102
- PubMed: 16289203
- DOI: 10.1016/j.jmb.2005.10.009
- Primary Citation of Related Structures:
- PubMed Abstract:
The DNA-binding and ligand-binding functions of nuclear receptors are localized to independent domains separated by a flexible hinge. The DNA-binding domain (DBD) of the human liver receptor homologue-1 (hLRH-1), which controls genes central to devel ...
The DNA-binding and ligand-binding functions of nuclear receptors are localized to independent domains separated by a flexible hinge. The DNA-binding domain (DBD) of the human liver receptor homologue-1 (hLRH-1), which controls genes central to development and metabolic homeostasis, interacts with monomeric DNA response elements and contains an Ftz-F1 motif that is unique to the NR5A nuclear receptor subfamily. Here, we present the 2.2A resolution crystal structure of the hLRH-1 DBD in complex with duplex DNA, and elucidate the sequence-specific DNA contacts essential for the ability of LRH-1 to bind to DNA as a monomer. We show that the unique Ftz-F1 domain folds into a novel helix that packs against the DBD but does not contact DNA. Mutations expected to disrupt the positioning of the Ftz-F1 helix do not eliminate DNA binding but reduce the transcriptional activity of full-length LRH-1 significantly. Moreover, we find that altering the Ftz-F1 helix positioning eliminates the enhancement of LRH-1-mediated transcription by the coactivator GRIP1, an action that is associated primarily with the distantly located ligand-binding domain (LBD). Taken together, these results indicate that subtle structural changes in a nuclear receptor DBD can exert long-range functional effects on the LBD of a receptor, and significantly impact transcriptional regulation.
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.